If you are thinking about enough moisture to ruin the powder, no. If you are talking about enough moisture to change the volume to weight ratio, yes. Take small case like a 223 and drop a charge that completely fills the case to the top of the neck. Weigh that charge and write it down. Next time your reloading if there has been a humidity change repeat that using the same case and powder and compare the results. Let me know what you find, I have been challanged to do that several times but always lose the case I used or lose where I wrote down the first results.

If you are thinking about enough moisture to ruin the powder, no. If you are talking about enough moisture to change the volume to weight ratio, yes. Take small case like a 223 and drop a charge that completely fills the case to the top of the neck. Weigh that charge and write it down. Next time your reloading if there has been a humidity change repeat that using the same case and powder and compare the results. Let me know what you find, I have been challanged to do that several times but always lose the case I used or lose where I wrote down the first results.

I will give that a try, somehow though I cant see a powder dump with a fairly tight fitting rubber cap in a climate controlled reloading room allowing any significant moisture in.

__________________
"My greatest fear is that after my demise my wife will sell my guns for the price I told her I paid for them"
-don't know where it came from...but true

I was at the range last Friday and was talking to a guy there. He said he and a buddy were there at the same range a few years ago and were sighting in their muzzle loaders. Of course, there was some smalltalk going on between the two and then they resumed shooting. He told me that he was rudely interrupted while looking through his scope and settling in to take another shot when all of a sudden his buddy's scope flew over and hit him in the head. He (rather quickly) looked to see what the hell was going on and saw that his buddy's muzzle loader barrel was split from the fore end all the way down to right before the muzzle both on the upper portion and lower portion of the barrel. Turns out his friend loaded his gun, then got to talking, and forgot that he loaded it. He then proceeded to load it again!!! So there's two powder charges with a 300gr. bullet sandwiched in between. My guess is there was an immediate need to clean that stubborn "fouling" in the underwear of the shooter after that round.

Ouch, I can imagine getting powder confused would be a mistake I don't care to make. It makes me think i will keep my powders away from my loading bench, that way I have to deliberatly get up and seek out the specific powder I am wanting to use. I do try and make sure I reference my loading charts several times before I even get rolling on the loading. I also pin up my load chart on the wall that I'm loading as I work on it so I can constantly reference it.

Great tips guys, thank you!

I had a similar mishap! Had 2 brands of powder on the bench. I refilled the powder measure. When I was finished and wanted to pour the powder in the tin again I was not sure which brand I had topped it up with. I did not want to take chances and had to dischart all 60 cartridges with a kenetic bullet puller. I disposed the powder on the lawn since the 2 brands were nearly identical and again I did not want to take any chances. I agree with you - keep the other tins away from the loading area and keep only the one you use nearby.

Just wait till you stick a case in your sizing die. That will ruin a day real quick. Cause up intill you stick that first case you never had a reason to have a stuck case remover around. Then you have to go track one down. Unless you already have a tap, socket, and screw around.

The other one that I did twice was get a primer in upside down. That is just a little glitch though.

Just had to pick one up last night

I havn't had anything too bad yet, my roomate on the other had has had some issues. He's pretty new to reloading, and hadn't quite figured out his seating die yet. Loaded up about 50 .223 cases with 60 grain v-max's, but apparently did not adjust the die correctly, and mushroomed the shoulder of the cases about .005", just enough to keep them from chambering.

After a few little mistakes like forgetting to size one or two cases only to realize when the bullet seated way too loosely, I began developing a very rigid Method of Procedure with a few safety checks along the way.

I still have a lot of room for improvement. But, my quality/consistency is improving.